A physical layer circuit that functions as a communication physical layer, as exemplified by 1000 Base-T (IEEE 802.3ab), has an automatic negotiation function in order to establish communication, i.e., to achieve a link-up, with a communication destination. To establish the communication, the automatic negotiation function determines the communication setting information on the physical settings for communication with a physical layer circuit at the communication destination.
Related techniques include Patent Literatures 1 to 3 listed below.